To elucidate the factors which regulate and alter hepatic glycerolipid metabolism under a variety of different dietary, disease and hormonal conditions. Significant progress has been made in developing methods to measure in vivo and in vitro hepatic glycerolipid metabolism. These investigations will be considerably expanded and new efforts initiated utilizing isolated hepatocytes and hepatic cells in monolayers to elucidate further the important regulatory processes in hepatic glycerolipid metabolism. These studies will include an evaluation of the effects of metabolic perturbations on the major functions of the endoplasmic reticulum. Microsomal cytochrome P450 levels and mixed function oxidase activity will be measured under conditions which alter glycerolipid formation and change membrane structural components. Changes in the content of membrane lipids and proteins will be correlated with alterations in several functions of the endoplasmic reticulum. Bibliographic references: Fallon, H.J., J. Barwick, R.G. Lamb and H. van den Bosch. Studies of rat liver microsomal diglyceride acyltransferase and cholinephosphotransferase using microsomal-bound substrate: effects of high fructose intake. J. Lipid Res. 16:107-115, 1975. Liu, S., R.K. Ramsey ad H.J. Fallon. Effects of ethanol on hepatic microsomal drug-metabolizing enzymes in the rat. Biochem. Pharmacology 24:369-378, 1975.